The redirect URI in the request, https://blutschwerter.de/connected_account.php, does not match the ones authorized for the OAuth client. To update the authorized redirect URIs, visit: https://console.developers.google.com/apis/credentials/oauthclient/188036659666-fc7m66k0k4ri14go3913rjag4q455oe0.apps.googleusercontent.com?project=188036659666